Previous discussion indicates that law is produced by multiple - sometimes competing - sources. The highest authority for law in any jurisdiction (whether a nation, state, or locality) is usually that jurisdiction's constitution or charter. In Texas the highest authority for state and local law is the Texas Constitution of 1876 and its numerous amendments. The original state constitution and the 467 amendments adopted as of the end of 2010 constitute the body of state constitutional law.
Under the authority granted it by the state Constitution the Legislature may pass bills dealing with specific areas of public policy. If the Governor approves them, these bills become laws, or statutes, joining the rest of the body of Texas statutory law.
On the local level cities can pass ordinances in a wide range of policy areas from traffic and parking rules to building codes, and more. These local laws can be approved either directly by city councils or by popular vote in a referendum election. Notably, counties in Texas serve as extensions of the Legislature and by constitutional design have virtually no law making authority of their own.
Law in Texas is not restricted to the state-level sources. Just as in all other states, a considerable body of law is produced by the federal government. Ultimately all law on all levels within the state must be consistent with the Constitution of the United States. The national Constitution, however, is not very restrictive. Except for the broad specification of requirements and terms for senators and representatives in the U.S. Congress, the U.S. Constitution's influence on state and local law mainly takes the form of some restrictions on the regulation of commerce and the protection of individual rights and liberties.
The U.S. Constitution, its twenty-seven amendments and all federal judicial rulings pertaining to the Constitution and its amendments form the body of U.S. constitutional law.
Additionally, the U.S. Congress is empowered to pass national statutes, many of which have a direct impact on states. A prominent example would the amended Clean Air Act of 1990, which specifies among other things maximum levels of automobile emissions. Section 209 of the act prohibits states from enacting or enforcing their own standards:
No State or any political subdivision thereof shall adopt or attempt to enforce any standard relating to the control of emissions from new motor vehicles or new motor vehicle engines subject to this part. 
Finally, like the state executive branch, the federal executive departments and agencies are empowered by Congress to make and enforce rules related to the implementation of national programs and laws.
Federal law and judicial rulings pertaining to those laws constitute the body of national statutory law. Similarly, the rules and regulations created by the federal bureaucracy with congressional authorization, and court rulings related to those rules, constitute the body of national administrative law.